1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a semiconductor device for detecting defective memory elements and automatically replacing them with redundant memory elements.
2. Description of the Related Art
Heretofore, to detect defective memory elements in a memory, data written into and read from the memory is examined by the use of an external tester. For remedying memories, that is, for replacing defective memory elements with redundant memory elements, connections to the defective memory elements are disconnected by electrical means or laser irradiation, the contents of the defective memory elements are stored by a spare memory section, or an address comparison with inspecting elements is made to detect defective memory elements, such as word lines, bit lines or defective decoders.
On the other hand, a redundant circuit involved in a memory is reduced in size as the integration density in semiconductor devices increases. Under such a situation, the remedy for memories by means of disconnection of wiring becomes increasingly difficult because of a decrease in reliability due to the disconnection of elements in multilevel interconnection structures of semiconductor devices, limitations on the reduction of the spot of a laser beam used for disconnection of wiring, and limitations on positioning accuracy due to the influence of passivation films of semiconductor devices.